Rob: in a properly installed and maintained system this earthing statment is true. A relativly new (compared to the age of most plumbing ) plumbing system using plastic piping for both hot and cold water can unintentionaly defeat the intrinsic safety of older plumbing and electrical grounding systems if used to replace part of the older bonded metal plumbing. Every thing on the ungrounded side of the repair could become hot in the event of a fault yet not trip a breaker until current flows probably through a human. In Canada This product is called PEX and I presume that it is in use world wide under various names. it is much less expensive and much safer to install than soldered copper No flames in among the cobwebs. It is not the product that is the problem it is the unexpected loss of ground continuity resulting from the use of it. Terry